BrJ Sports Med 1996;30:134-139 Low back pain and other overuse injuries in a group ofJapanese triathletes

Objective-To document the incidence of low back pain and other overuse injuries in a group oftriathletes, and to investigate any associations with various physical and triathlon related factors. Methods-By means ofa questionnaire, the physical characteristics, training habits, and the incidences of overuse injuries of 92 Japanese triathletes (70 males, 22 females) were documented. Student's t and x2 tests were used to determine the significance of any associations with injury incidence, as well as differences between subjects experiencing or not experiencing low back pain in the previous year. Results-Low back pain was experienced by 32% ofsubjects in the previous year. The majority (54%) of low back pain episodes lasted under seven days, suggesting mainly soft tissue involvement, and 19% lasted over three months, suggesting involvement of the intervertebral discs. Weekly trunk flexor muscle training frequency was significantly greater (P = 0.035) for the low back pain subjects. Close to significant differences for average weekly cycling time, trunk flexor muscle training time, and low intensity aerobic rining, as well near significant associations for weight training and average weekly triathlon taining load, were also found. No other factors were significantly associated with low back pain. Low back injuries accounted for 28% of all injuries. Only the knee was a more common single site ofinjury (33%/o). Conclusions-The three most common injuries suffered by the triathletes were of the knee, back and shoulder. The low back pain suffered by many triathletes could be of a potentially serious nature. It is suggested that cycling is a major risk factor for low back pain in triathletes. (BrJ Sports Med 1996;30:134-139) Department ofHealth Sciences, University of' JyvdskylA, Finland J S 0 Manninen M Kallinen The study was carried out at the Institute of Sports Medicine and Science, Agui, Japan Correspondence to: Jyri Seppo Manninen, 1046 NW 9th Street, Corvallis Oregon 97330, USA Accepted for publication 8June 1995 Key terms: low back pain; triathlon; injury; cycling Triathlon is an endurance sport involving swimming, cycling, and running. It has officially existed only for about 20 years, and during this time has developed very rapidly with regard to training strategies and cycling technology. Because of the short history of the sport, it has been very difficult to evaluate, or even predict, its long term physical effects (that is, sports related factors) on the participants. It is really only in the new or younger generation of triathletes, for many of whom triathlon was their first sport, that these long term effects can be monitored and investigated more accurately. Data on triathlete injuries are sparse, and the most recent studies were performed some five years ago'`7 This, along with the above mentioned rapid development of the sport especially in recent years indicates the strong need for further more comprehensive investigation into triathlon related injuries. It has been argued that triathlon, as a multisport event, causes less overuse injuries than single sports, because of the more even distribution of loads over the body's musculoskeletal structures. Despite this, triathletes still suffer from a high degree of overuse injuries. These overuse injuries also account for as much as 85% of all injuries suffered.3' One commonly injured site is the low back. 15 The main purposes of this study were to document the incidence of low back pain and other overuse injuries in a group of triathletes, and to investigate the associations between certain physical and triathlon related factors and the incidence of low back pain.